1. Field of the Invention
The present invention relates to yellow toners used in recording methods such as electrophotographies, electrostatic recording methods, magnetic recording methods, and toner jet methods.
2. Description of the Related Art
In recent years, color images have spread widely and the demand for high-quality images has been raised. In digital full-color copying machines and printers, color-image manuscripts are color-separated by each color filter of blue, green, and red, and thereafter, latent images corresponding to the original images are developed using each color developer of yellow, magenta, cyan, and black. Thus, the coloring power of a colorant in the each color developer largely affects the image quality.
The reproduction of color spaces including the Japan Color in print industries and AdobeRGB in DeskTop Publishing (DTP) is becoming important. For the reproduction of the color spaces, a method is known in which a dye having a broad color gamut is used in addition to improvement of dispersibility of a pigment.
Typical examples known as yellow colorants for toners are isoindolinone, quinophthalone, isoindoline, anthraquinone, and compounds having an azo skeleton or the like. Among these, some examples of yellow dyes are known which use an azo skeleton like C.I. Solvent Yellow 162 high in transparency and coloring power and excellent in light resistance (see Japanese Patent Application Laid-Open No. S61-112160, Japanese Patent Application Laid-Open No. H07-140716 and Japanese Patent Application Laid-Open No. H11-282208).
Particularly in the case of using a compound having an azo skeleton like C.I. Solvent Yellow 162 as a yellow colorant for toners, a yellow toner excellent in color development in a yellow color gamut can be obtained from the feature of the dye.
However, a further improvement is needed for making the chroma better and broadening the green color gamut.